Implement phased rollout in the updater

[Pedro-Souza]

Context

Currently, when a new version is released, all users receive the update immediately.
This creates risks, since potential bugs or regressions would impact 100% of the user base at once.

Problem

We need a way to gradually release updates to users.
By doing so, we can limit exposure, monitor stability, and increase the rollout percentage over time until all users receive the update.

Requirements

• Each client must send a unique ID when checking for updates (the client decides what the unique ID will be).
• The server must determine whether a given ID is eligible for the current rollout.
• Users who already received the version must continue to get it, even if the rollout percentage changes.

Proposed Solution

• Use Statsig (or another feature flag/rollout tool) to manage rollout percentages.

[jlcarvalho]

Only the Statsig part that I don't know if it's the best option.

I know that creating an UI to manage this may be overkill, but perhaps an API with basic auth to save the rollout configs on redis would be good enough and makes us less dependant of third parties.